The asymmetric unit of the title compound, C(3)H(12)N(2) (2+)·2C(6)H(4)NO(2) (-)·H(2)O, consists of half of a doubly protonated propane-1,3-diammonium dication, a pyridine-4-carboxyl-ate anion and half of a solvent water mol-ecule; the dication and the solvent water are located on a twofold rotation axis which passes through the central C atom of the dication and the water O atom. The carboxyl-ate group of the anion appears to be delocalized on the basis of the C-O bond lengths. In the crystal, the components are linked by inter-molecular N-H⋯O, N-H⋯N and O-H⋯O hydrogen bonds.